Enhancing audio using a mobile device

ABSTRACT

Embodiments disclosed herein enable detection and improvement of the quality of the audio signal using a mobile device by determining the loss in the audio signal and enhancing audio by streaming the remainder portion of audio. Embodiments disclosed herein enable an improvement in the sound quality rendered by rendering devices by emitting an test audio signal from the source device, measuring the test audio signal using microphones, detecting variation in the frequency response, loudness and timing characteristics using impulse responses and correcting for them. Embodiments disclosed herein also compensate for the noise in the acoustic space by determining the reverberation and ambient noise levels and their frequency characteristics and changing the digital filters and volumes of the source signal to compensate for the varying noise levels.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 14/449,159, filed on Aug. 1, 2014, which claims priority toU.S. Provisional Application No. 61/861,138 filed on Aug. 1, 2013, theentireties of which are incorporated herein.

BACKGROUND

1. Technical Field

The embodiments herein relate to enhancing audio rendered by at leastone rendering device and, more particularly, to enhancing audio renderedby at least one rendering device using a mobile device.

2. Description of Related Art

Currently, a user may have access to audio data (such as an audio file,a video file with an audio track and so on) in a plurality of placessuch as his residence, office, vehicle and so on. The user may also usea plurality of devices to access the audio data such as his mobilephone, tablet, television, computer, laptop, wearable computing devices,CD (Compact Disc) player and so on.

To listen to the audio, the user may use external systems (such as ahome theater system, car speakers/tweeters/amplifiers and so on) orinternal systems (such as speakers inbuilt to the device playing theaudio) and so on. There may be a plurality of issues faced by the user,when listening to the audio.

The audio data may be of poor quality. For example, audio electronicstorage files (such as MP3 and so on) may have poor quality. In anotherexample, the audio data received over the Internet may be of poorquality (which may be caused by poor quality of the audio file availableon the internet, a poor internet connection and so on). This case may beconsidered where the audio ‘signal’ is of poor quality.

The devices, which render the audio to the user, may be of poor quality.Furthermore, the acoustic space in which the device is placed affectsthe quality of these devices. These devices, which render the audio, maybe built using various different components that are not matched to eachother, resulting in loss of audio quality.

Also, ambient noise (such as traffic noise in a car) may result in aloss in the audio quality audible to the user. The ambient noise levelof the acoustic space may also vary over time. For example, depending ofthe speed or the type of the road, the ambient noise in a car may vary.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The embodiments herein will be better understood from the followingdetailed description with reference to the drawings, in which:

FIG. 1 depicts a system comprising of a source device and at least onerendering device, according to embodiments as disclosed herein.

FIG. 2 depicts a mobile device being used to enhance audio data from asystem comprising of a source device and at least one rendering device,according to embodiments as disclosed herein.

FIGS. 3a, 3b, 3c, 3d, 3e and 3f depict illustrations where the mobiledevice is located with respect to the source device and the renderingdevice, according to embodiments as disclosed herein.

FIG. 4 is a flowchart illustrating the process of enhancing audio data,according to embodiments as disclosed herein.

FIG. 5 depicts a mobile device, according to embodiments as disclosedherein.

FIG. 6 is a flowchart illustrating the process of determining microphonecharacteristics of a mobile device, according to embodiments asdisclosed herein.

FIG. 7 is a flowchart illustrating the process of detecting quality of asource signal and improving the quality of the source signal, accordingto embodiments as disclosed herein.

FIGS. 8a and 8b are flowcharts illustrating the process of calibratingat least one rendering device using a mobile device, according toembodiments as disclosed herein.

FIG. 9 is a flowchart illustrating the process of improving acousticquality based on ambient noise, according to embodiments as disclosedherein.

FIG. 10 illustrates a computing environment implementing the method forenhancing audio quality, according to embodiments as disclosed herein.

DETAILED DESCRIPTION

The embodiments herein and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments that are illustrated in the accompanying drawings anddetailed in the following description. Descriptions of well-knowncomponents and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. The examples used hereinare intended merely to facilitate an understanding of ways in which theembodiments herein may be practiced and to further enable those of skillin the art to practice the embodiments herein. Accordingly, the examplesshould not be construed as limiting the scope of the embodiments herein.

The embodiments herein disclose a method and system for enhancing audioquality using a mobile device. Referring now to the drawings, and moreparticularly to FIGS. 1 through 10, where similar reference charactersdenote corresponding features consistently throughout the figures, thereare shown embodiments.

Embodiments herein disclose a method and system for improving theoverall quality of audio for a user by detecting a plurality of qualityparameters. Using the measured quality parameters, the audio signal isprocessed in a manner such that the sound quality output is improved.The quality parameters that may be calculated are as follows: sourcesignal quality (this parameter determined how good the source signal iscompared to a similar very high-quality audio signal), calibration ofthe rendering device (parameters are calculated based on a calibrationsignal which may be used to determine overall quality of a renderingdevice and based on the quality of the rendering device, a digitalsignal processing algorithm is designed that does equalization, loudnesscorrection and timing synchronization of the rendering devices) andacoustic quality of the space in which the rendering device is operating(this determines the noise level and characteristics in an acousticspace).

FIG. 1 depicts a system comprising of a source device and at least onerendering device, according to embodiments as disclosed herein. Thesystem comprises of a source device 101 and at least one renderingdevice 102. The source device 101 may be a device configured to readaudio data. The audio data may be an audio file, a video file with anaudio clip (such as a movie, television series, documentaries and soon), a video game and so on. The source device 101 may be a mobilephone, a tablet, a television, a CD player, a DVD player, a Blu-rayplayer, a laptop, a computer and so on. The source device 101 mayfurther comprise of a means to display visual data such as a display,monitor and so on. The source device 101 may access the audio data byreading the audio data from a data storage means such as a CD, DVD,Blu-Ray, flash drive, internal storage or any other form of storage,which may contain audio data. The source device 101 may stream the audiodata from a network location such as the Internet, a LAN (Local AreaNetwork), a WAN (Wide Area Network) and so on.

The rendering device 102 may be a device, which enables the audio datato be made audible to a user. The rendering device 102 may be a speaker,an amplifier, a tweeter, a headphone, a headset and so on. The renderingdevice 102 may be inbuilt with the source device 101. The renderingdevice 102 may be located remotely from the source device 101 and maycommunicate with the source device 101 using a suitable means such as awired means, wireless means (Bluetooth, Wi-Fi and so on). There may beat least one rendering device connected to the source device 101.

FIG. 2 depicts a mobile device being used to enhance audio data from asystem comprising of a source device and at least one rendering device,according to embodiments as disclosed herein. The source device 101 andthe at least one rendering device 102 are connected to each other. Thespace where the audio data from the source device 101 and the renderingdevice 102 is audible is hereinafter referred to as an acoustic space.The mobile device 201 may be connected to the source device 101 througha suitable communication means such as a wired means, wireless means andso on. The mobile device 101 may be configured to receive audio datafrom the rendering device 102 through a suitable means such as amicrophone and so on. The mobile device 201 may be a mobile phone, atablet, a computer, a laptop or any other device capable of receivingaudio data and perform analysis on audio data.

The source device 101 and the rendering device 102 may be present withinthe same device and connected to the mobile device 201 using a suitableconnection means (as depicted in FIG. 3a ). The source device 101 andthe rendering device 102 may be located within the mobile device 201 (asdepicted in FIG. 3b ). The source device 101 may be co-located with themobile device 201, with the rendering device 102 located remotely fromthe mobile device 201 (as depicted in FIG. 3c ). The source device 101may be connected to a plurality of rendering devices 102, with themobile device 201 being located within the acoustic space, wherein theacoustic space is an areas such as a room, a stage, a theater, anamphitheater, a stadium and so on (as depicted in FIGS. 3d and 3e ). Thesource device 101, the rendering device 102 and the mobile device 201may be co-located within a vehicle (as depicted in FIG. 30.

The mobile device 201, on detecting audio being played, may obtain thefrequency characteristics of the microphone of the mobile device 201.The mobile device 201 may determine the frequency characteristics usinga stored profile of the mobile device 201 stored in a suitable locationwithin the mobile device 201 or external to the mobile device 201. Themobile device 201 may further determine the quality of the source signaland improve the quality of the source signal. The mobile device 201 maythen perform calibration of the rendering devices 102. The calibrationmay be in terms of modifying equalization settings. The mobile device201 may further compensate for ambient noise. The mobile device 201 maycommunicate settings related to the calibration and the ambient noisecompensation to the source device 101.

FIG. 4 is a flowchart illustrating the process of enhancing audio data,according to embodiments as disclosed herein. The mobile device 201, ondetecting audio being played, obtains (401) the frequencycharacteristics of the microphone of the mobile device 201. The mobiledevice 201 may determine the frequency characteristics using a storedprofile of the mobile device 201 stored in a suitable location withinthe mobile device 201 or external to the mobile device 201. The mobiledevice 201 may calculate the frequency characteristics of the mobiledevice 201. The mobile device 201 further determines (402) the qualityof the source signal and improves the quality of the source signal. Themobile device 201 then calibrates (403) the rendering devices 102. Thecalibration may be in terms of modifying equalization settings. Themobile device 201 further compensates (404) for ambient noise. Themobile device 201 communicates the improved source signal, settingsrelated to the calibration and the ambient noise compensation to thesource device 101. The various actions in method 400 may be performed inthe order presented, in a different order or simultaneously. Further, insome embodiments, some actions listed in FIG. 4 may be omitted.

FIG. 5 depicts a mobile device, according to embodiments as disclosedherein. The mobile device 201, as depicted, comprises of a controller501, at least one microphone 502, a communication interface 503 and amemory 504.

The controller 501 may determine the frequency characteristics of themicrophone 502. The controller 501 may fetch the frequencycharacteristics of the microphone 502 from the memory 504. Thecontroller 501 may communicate a test audio signal to the source device101, wherein the test audio signal may be a logarithmic test sweepsignal. The source device 101 may play the test audio signal using therendering device 102. The controller 501 may capture the test signalfrom the rendering device 102 using the microphone 502, wherein themobile device 201 may be placed at a very close range to the renderingdevice 102. The controller 501 may guide the user through theabove-mentioned steps. The controller 501 may then determine the impulseresponse of the captured test signal. The controller 501 may invert thefrequency characteristics of the impulse response and may determine amicrophone-equalizing filter, wherein the microphone-equalizing filtermay be used to compensate for the frequency characteristics of themicrophone 502. The controller 502 may store the microphone-equalizingfilter in the memory 504 and may be used in the further steps.

The controller 501, on detecting that audio is being played though themicrophone 502 may use the detected audio signal and a suitable audiofingerprinting means to identify the audio being played. On identifyingthe audio, the controller 501 may fetch a small portion of ahigh-quality version of the detected audio signal from a location (suchas the internet, the LAN, the WAN, a dedicated server and so on). Thecontroller 501 may time align the detected audio signal and the fetchedaudio signal. The controller 501 may perform the time alignment bycomparing the detected audio signal and time shifted versions of thefetched audio signal. Once the signals are time aligned, the controller501 may calculate a metric related to the difference between thehigh-quality fetched audio signal and the original source signal usingthe formula:

Sq=(H*H+O*O)/(H−O)*(H−O)

Where H is the fetched audio signal, O is the detected audio signal andSq is the quality of the detected audio signal. The controller 501 maycheck if the source signal is of a low quality by comparing Sq with aquality threshold. If Sq is less than the threshold, then the controller501 may determine that the source signal is of low quality. If thesource signal is of low quality, the controller 501 may detect a highquality source of the sound signal from a suitable location (such as theInternet, a LAN, a WAN, a dedicated server and so on) and stream thehigh-quality signal from the suitable location. The controller 501 maytransmit the difference signal between the low quality and high qualitysignal to the source device 101, which results in an improvement in thequality of the source signal.

The controller 501 may determine the setup of the rendering devices(number of rendering devices, locations of the rendering devices, typesof rendering devices and so on). In an embodiment herein, the controller501 may use the sensors of the mobile device 201 such as themagnetometer and accelerometer to measure angles with respect to therendering devices. The magnetometer may provide the initial referencedirection and the accelerometer may be used to give the angulardisplacement from the initial reference direction. The controller 501may obtain the absolute angles of the locations of the rendering deviceswith respect to the reference position. The controller 501 may provideinstructions to the user to point the mobile device 201 toward therendering device and the controller 501 determines the Cartesiancoordinates. In another embodiment herein, the controller 501 may promptthe user to input the coordinates of the rendering devices. In anotherembodiment herein, the controller 501 may use the microphones totriangulate and find the location of the rendering devices.

The controller 501 may determine the relative distances of the renderingdevices by providing a known reference signal to the source device 101.The source device 101 may play the reference signal at periodicintervals (wherein the periodic intervals may be determined by thecontroller 501). The controller 501 may capture the reference signalsplayed from the rendering devices using the microphone 502. Thecontroller 501 may determine the relative distances of the renderingdevices by calculating the delays.

The controller 501 may further check the acoustics of the acousticspace. The controller 501 may use impulse response (IR) method to findthe frequency response, distance and loudness of the rendering devicesand the acoustic space. The controller 501 may first send a test tone ora calibration audio signal, preferably an audio signal frequency sweep,to the rendering device (through the source device). The controller 501may capture back the calibration signal using the microphone 502. Thecontroller 501 may calculate an impulse response for the broadcastcalibration audio signal. The controller may take the inverse Fouriertransform (FFT) of the ratio of the FFT of the frequency sweep signaland FFT of the received microphone signal. This impulse response mayrepresent the quality of the audio signal in the current acoustic space.

In one embodiment, the controller 501 may calculate a crossover filterusing the impulse response, wherein the crossover filter may be appliedto the rendering device 102. The cross-over filter may be a fourth orderButterworth filter, wherein the cut-off of the Butterworth filter may bedetermined by the controller 501 from the frequency response of theimpulse response. In an embodiment herein, the controller 501 mayconsider the point at which the amplitude of the frequency responsedrops to −10 dB of the maximum amplitude over the entire frequency rangeas the cut-off frequency.

In another embodiment, the controller 501 may determine the loudness ofthe rendering device using the impulse response. The controller 501 maycompute the loudness by calculating the energy of the impulse response.The controller 501 may use a well-known weighting filter, such asA-weights or C-weights for computation of this loudness in conjunctionwith the impulse response. After determining the loudness of therendering device, the controller 501 may determine the loudnesscompensation by computing the average of the magnitude of all thefrequency responses for the rendering device. The controller 501 may usethe inverse of the average of the magnitude of all the frequencyresponses for the rendering device to match the volume of eachsubsequent rendering device (if any).

In one embodiment, the controller 501 may mimic the non-linear frequencyscale of a human auditory system by passing the impulse response througha set of all-pass filters. This filtered signal is hereinafter referredto as ‘m’. The controller 501 may compute a finite impulse response(FIR) filter (hereinafter referred to as w), which is the minimum phasefilter whose magnitude response is the inverse of m. The controller 501may invert the non-linear frequency scale to yield the finalequalization filter by passing the FIR w through a set of all-passfilters, wherein the final equalization filter may be used to compensatethe quality of rendering device. The controller 501 may repeat thisprocess for all the rendering devices.

In an embodiment herein, the controller 501 may use an infinite impulseresponse (IIR) filter to correct the response of the rendering device.In an embodiment herein, the controller 501 may use a combination of FIRand IIR filters may be used to correct the response of the renderingdevice.

In order to synchronize multiple rendering devices in time, thecontroller 501 may calculate a delay compensation by first calculatingthe delay between broadcast of the calibration signal from each of therendering devices and the corresponding receipt of such signal at themicrophone, preferably through examination of the point at which theimpulse repulse is at its maximum. The controller 501 may then obtain adelay compensation filter by subtracting the delay from a pre-determinedmaximum delay (which may be configured by the user at the source device101). The controller 501 may estimate a delay filter for thesubject-rendering device 102 for later compensation of any uneven timingof the previously determined impulse response.

The controller 501 may account for the different ambient noise levelsduring playback of the audio signal through the rendering devices. Thecontroller 501 may use the microphone 502. On detecting a period ofsilence in the source signal, the controller 501 through the microphone502, measure ambience noise characteristics. The ambient noisecharacteristics may comprise of frequency characteristics and loudnesslevel of noise, during this period of silence. The controller 501 maymeasure loudness using a suitable method (such as A-weights) that canmimic human hearing. The controller 501 may calculate the frequencyresponse using the FFT of the detected noise signal. The controller 501uses the inverse of the frequency response to calculate a digital filter(wherein the digital filter may be at least one of FIR or IIR) tocompensate for the noise characteristics. The controller 501 may alsoestimate an optimum volume level of the source signal, based on theloudness level of the noise so as to keep constant power between thenoise and the source signal. The controller 501 may communicate thedigital filter and the optimum noise level to the source device 101,which performs adjustments as per the received communication.

FIG. 6 is a flowchart illustrating the process of determining microphonecharacteristics of the microphone of a mobile device, according toembodiments as disclosed herein. The mobile device 201 communicates(601) a test audio signal to the source device 101, wherein the testaudio signal may be a logarithmic test sweep signal. The source device101 plays (602) the test audio signal using the rendering device 102.The mobile device 201 captures (603) the test signal from the renderingdevice 102 using the microphone 502, wherein the mobile device 201 maybe placed at a very close range to the rendering device 102. The mobiledevice 201 then determines (604) the impulse response of the capturedtest signal. The mobile device 201 inverts (605) the frequencycharacteristics of the impulse response and determines (606) amicrophone-equalizing filter, wherein the microphone-equalizing filtermay be used to compensate for the frequency characteristics of themicrophone 502. The controller 502 stores (607) the microphoneequalizing filter in the memory 504 and may be used in the furthersteps. The various actions in method 600 may be performed in the orderpresented, in a different order or simultaneously. Further, in someembodiments, some actions listed in FIG. 6 may be omitted.

FIG. 7 is a flowchart illustrating the process of detecting quality of asource signal and improving the quality of the source signal, accordingto embodiments as disclosed herein. The mobile device 201, on detectingthat audio is being played though the microphone 502 identifies (701)the audio being played using the detected audio signal and a suitableaudio fingerprinting means. On identifying the audio, the mobile device201 fetches (702) a small portion of a high-quality version of thedetected audio signal from a location (such as the internet, the LAN,the WAN, a dedicated server and so on). The mobile device 201 timealigns (703) the detected audio signal and the fetched audio signal bycomparing the detected audio signal and time shifted versions of thefetched audio signal. Once the signals are time aligned, the mobiledevice 201 calculates (704) the metric related to the difference betweenthe high-quality downloaded signal and the original source signal usingthe formula:

Sq=(H*H+O*O)/(H−O)*(H−O)

Where H is the fetched audio signal, O is the detected audio signal andSq is the quality of the detected audio signal. The mobile device 201checks (705) if the source signal is of a low quality by comparing Sqwith a quality threshold. If Sq is less than the threshold, then themobile device 201 may determine that the source signal is of lowquality. If the source signal is of low quality, the mobile device 201detects (706) a high quality source of the sound signal from a suitablelocation (such as the Internet, a LAN, a WAN, a dedicated server and soon) and streams (707) the high-quality signal from the suitablelocation. The mobile device 201 transmits (708) the difference signalbetween the low quality and high quality signal to the source device101, which results in an improvement in the quality of the sourcesignal. The various actions in method 700 may be performed in the orderpresented, in a different order or simultaneously. Further, in someembodiments, some actions listed in FIG. 7 may be omitted.

FIGS. 8a and 8b are flowcharts illustrating the process of calibratingat least one rendering device using a mobile device, according toembodiments as disclosed herein. The mobile device 201 may determine thesetup of the rendering devices (number of rendering devices, locationsof the rendering devices, types of rendering devices and so on). In anembodiment herein, the mobile device 201 may use the sensors of themobile device 201 such as the magnetometer and accelerometer to measureangles with respect to the rendering devices. The magnetometer provides(801) the initial reference direction and the accelerometer provides(802) the angular displacement from the initial reference direction. Themobile device 201 obtains (803) the absolute angles of the locations ofthe rendering devices with respect to the reference position in terms ofCartesian coordinates. The mobile device 201 may provide instructions tothe user to point the mobile device 201 toward the rendering device 102.In another embodiment herein, the mobile device 201 may prompt the userto input the coordinates of the rendering devices. In another embodimentherein, the mobile device 201 may use the microphones to triangulate andfind the location of the rendering devices. The mobile device 201determines the relative distances of the rendering devices by providing(804) a known reference signal to the source device 101. The sourcedevice 101 plays (805) the reference signal at periodic intervals(wherein the periodic intervals may be determined by the mobile device201). The mobile device 201 captures (806) the reference signals playedfrom the rendering devices using the microphone 502. The mobile device201 determines (807) the relative distances of the rendering devices bycalculating the delays of the captured reference signals.

The mobile device 201 may further check the acoustics of the acousticspace. The mobile device 201 uses impulse response (IR) method to findthe frequency response, distance and loudness of the rendering devicesand the acoustic space. The mobile device 201 first sends (808) a testtone or a calibration audio signal, preferably an audio signal frequencysweep signal, to the rendering device 102 (through the source device101). The mobile device 201 captures (809) back the calibration signalusing the microphone 502. The mobile device 201 calculates (810) animpulse response for the frequency sweep signal by taking the inverseFourier transform (IFT) of the ratio of the FFT (Fast Fourier Transform)of the frequency sweep signal and FFT of the received microphone signal.

In one embodiment, the mobile device 201 calculates (811) a crossoverfilter using the impulse response, wherein the crossover filter may beapplied to the rendering device 102. The cross-over filter may be afourth order Butterworth filter, wherein the cut-off of the Butterworthfilter may be determined by the mobile device 201 from the frequencyresponse of the impulse response. In an embodiment herein, the mobiledevice 201 may consider the point at which the amplitude of thefrequency response drops to −10 dB of the maximum amplitude over theentire frequency range as the cut-off frequency.

In another embodiment, the mobile device 201 determines (812) theloudness of the rendering device using the impulse response. The mobiledevice 201 may compute the loudness by calculating the energy of theimpulse response. The mobile device 201 may use a well known weightingfilter, such as A-weights or C-weights for computation of this loudnessin conjunction with the impulse response. After determining the loudnessof the rendering device, the mobile device 201 determines (813) theloudness compensation by computing the average of the magnitude of allthe frequency responses for the rendering device. The mobile device 201may use the inverse of the average of the magnitude of all the frequencyresponses for the rendering device to match the volume of eachsubsequent rendering device (if any).

In one embodiment, the mobile device 201 mimics (814) the non-linearfrequency scale of a human auditory system by passing the impulseresponse through a set of all-pass filters. This filtered signal ishereinafter referred to as ‘m’. The mobile device 201 computes (815) afinite impulse response (FIR) filter (hereinafter referred to as w),which is the minimum phase filter whose magnitude response is theinverse of m. The mobile device 201 inverts (816) the non-linearfrequency scale to yield the final equalization filter by passing theFIR w through a set of all-pass filters, wherein the final equalizationfilter may be used to compensate the quality of rendering device. Themobile device 201 repeats (817) this process for all the renderingdevices.

In an embodiment herein, the mobile device 201 may use an infiniteimpulse response (IIR) filter to correct the response of the renderingdevice. In an embodiment herein, the mobile device 201 may use acombination of FIR and IIR filters may be used to correct the responseof the rendering device.

In order to synchronize multiple rendering devices in time, the mobiledevice 201 calculates a delay compensation by first calculating thedelay between broadcast of the calibration signal from each of therendering devices and the corresponding receipt of such signal at themicrophone, preferably through examination of the point at which theimpulse repulse is at its maximum. The mobile device 201 then obtains adelay compensation filter by subtracting the delay from a pre-determinedmaximum delay (which may be configured by the user at the source device101). The mobile device 201 may estimate a delay filter for thesubject-rendering device 102 for later compensation of any uneven timingof the previously determined impulse response.

The various actions in method 800 may be performed in the orderpresented, in a different order or simultaneously. Further, in someembodiments, some actions listed in FIGS. 8a and 8b may be omitted.

FIG. 9 is a flowchart illustrating the process of improving acousticquality based on ambient noise, according to embodiments as disclosedherein. The mobile device 201 may account for the different ambientnoise levels during playback of the audio signal through the renderingdevices. The mobile device 201 may use the microphone 502. On detectinga period of silence in the source signal, the mobile device 201 throughthe microphone 502, measures (901) ambience noise characteristics. Theambient noise characteristics may comprise of frequency characteristicsand loudness level of noise, during this period of silence. The mobiledevice 201 measures (902) loudness using a suitable method (such asA-weights) that can mimic human hearing. The mobile device 201calculates (903) the frequency response using the FFT of the detectednoise signal. The mobile device 201 calculates (904) a digital filter(wherein the digital filter may be at least one of FIR or IIR) using theinverse of the frequency response, to compensate for the noisecharacteristics. The mobile device 201 also estimates (905) an optimumvolume level of the source signal, based on the loudness level of thenoise so as to keep constant power between the noise and the sourcesignal. The mobile device 201 communicates (906) the digital filter andthe optimum noise level to the source device 101, which performsadjustments as per the received communication. The various actions inmethod 900 may be performed in the order presented, in a different orderor simultaneously. Further, in some embodiments, some actions listed inFIG. 9 may be omitted.

FIG. 10 illustrates a computing environment implementing the method forenhancing audio quality, according to embodiments as disclosed herein.As depicted the computing environment 1001 comprises at least oneprocessing unit 1004 that is equipped with a control unit 1002 and anArithmetic Logic Unit (ALU) 1003, a memory 1005, a storage unit 1006,plurality of networking devices 1010 and a plurality Input output (I/O)devices 1007. The processing unit 1004 is responsible for processing theinstructions of the algorithm. The processing unit 1004 receivescommands from the control unit in order to perform its processing.Further, any logical and arithmetic operations involved in the executionof the instructions are computed with the help of the ALU 1003.

The overall computing environment 1001 may be composed of multiplehomogeneous and/or heterogeneous cores, multiple CPUs of differentkinds, special media and other accelerators. The processing unit 1004 isresponsible for processing the instructions of the algorithm. Further,the plurality of processing units 1004 may be located on a single chipor over multiple chips.

The algorithm comprising of instructions and codes required for theimplementation are stored in either the memory unit 1005 or the storage1006 or both. At the time of execution, the instructions may be fetchedfrom the corresponding memory 1005 and/or storage 1006, and executed bythe processing unit 1004.

In case of any hardware implementations various networking devices 1008or external I/O devices 1007 may be connected to the computingenvironment to support the implementation through the networking unitand the I/O device unit.

Embodiments disclosed herein enable detection and improvement of thequality of the audio signal using a mobile device. Embodiments hereinuse the audio attributes such as bit rate of audio and the network linkquality and along with fingerprint of audio to determine the audioquality. Since most of the audio, which is stored or streamed, iscompressed using lossy compression, there may be missing portions ofaudio. Embodiments disclosed herein determine this loss and enhancesaudio by streaming the remainder portion of audio.

Embodiments disclosed herein enable an improvement in the sound qualityrendered by rendering devices. By emitting the test audio signal fromthe source device and measuring the test audio signal using microphones,embodiments disclosed herein understand the acoustics characteristics ofthe rendering device. Embodiments disclosed herein then detect variationin the frequency response, loudness and timing characteristics usingimpulse responses and corrects for them.

Embodiments disclosed herein also compensate for the noise in theacoustic space. Using the microphone of the mobile device, embodimentsdisclosed herein determine the reverberation and ambient noise levelsand their frequency characteristics in the acoustic space and changesthe digital filters and volumes of the source signal to compensate forthe varying noise levels in the acoustic space.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the embodiments herein that others may, byapplying current knowledge, readily modify and/or adapt for variousapplications such specific embodiments without departing from thegeneric concept, and, therefore, such adaptations and modificationsshould and are intended to be comprehended within the meaning and rangeof equivalents of the disclosed embodiments. It is to be understood thatthe phraseology or terminology employed herein is for the purpose ofdescription and not of limitation. Therefore, while the embodimentsherein have been described in terms of preferred embodiments, thoseskilled in the art will recognize that the embodiments herein may bepracticed with modification within the spirit and scope of the claims asdescribed herein.

Example Embodiments

In an embodiment, method for improving audio quality of an audio systemcomprising of a source device and at least one rendering device using amobile device includes improving quality of a source audio signal by themobile device, if the quality of the source signal is below a qualitythreshold, wherein the source audio signal is being played on the audiosystem, calibrating the at least one rendering device by the mobiledevice, and compensating for ambient noise by the mobile device.

The method may further include obtaining frequency characteristics of atleast one microphone associated with the mobile device.

The obtaining frequency characteristics of the at least one microphoneassociated with the mobile device may include communicating a testsignal to the source device by the mobile device, capturing the testsignal by the at least one microphone, on the source device playing thetest signal through the rendering device, determining impulse responseof the captured test signal by the mobile device, inverting frequencycharacteristics of the impulse response by the mobile device,determining a microphone equalizing filter by the mobile device usingthe impulse response and the inverted frequency characteristics of theimpulse response, and using the microphone equalizing filter tocompensate for frequency characteristics of the at least one microphoneby the mobile device.

The determining the quality of the source audio signal by the mobiledevice may include identifying a detected source audio signal by themobile device, fetching a small portion of a high quality audio signalof the identified source audio signal by the mobile device, timealigning the fetched high quality audio signal and the detected sourceaudio signal by the mobile device, calculating a metric related todifference between the fetched high quality audio signal and thedetected source audio signal using Sq=(H*H+O*O)/(H−O)*(H−O), where H isthe fetched high quality audio signal, O is the detected source audiosignal and Sq is quality of the detected source audio signal, andcomparing the metric to the quality threshold by the mobile device todetermine the quality of the source audio signal.

The improving the quality of the source audio signal may includedetecting a high quality source of the source audio signal by the mobiledevice, streaming the high quality source of the source audio signal bythe mobile device, and transmitting the high quality source of the audiostream to the source device by the mobile device.

The calibrating the at least one rendering device by the mobile devicemay include obtaining absolute angles of location of the at least onerendering device in terms of Cartesian coordinates with respect to areference position by the mobile device, determining relative distancesof the rendering devices by the mobile device, capturing a calibrationsignal by the mobile device, wherein the calibration signal is sent tothe rendering device by the mobile device, calculating an impulseresponse for the calibration signal by the mobile device, wherein theimpulse response is a ratio of the FFT (Fast Fourier Transform) of thecalibration signal to the FFT of the received calibration signal,calculating a crossover filter using the impulse response by the mobiledevice, wherein the crossover filter is a fourth order Butterworthfilter, determining loudness of the rendering device using the impulseresponse by the mobile device, determining a loudness compensation bycomputing an average of magnitude of all frequency responses for therendering device by the mobile device, and correcting response of therendering devices by the mobile device.

The determining the relative distances of the rendering devices by themobile device may include capturing a reference signal by the mobiledevice, wherein the reference signal is provided by the mobile deviceand is played by the source device, and determining the relativedistances of the rendering devices by the mobile device by calculatingdelays in the captured reference signal.

The cut-off of the crossover filter may be based on the frequencyresponse of the impulse response.

The determining loudness of the rendering device using the impulseresponse may include calculating energy of the impulse response.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a finite impulse response (FIR) filterby the mobile device, wherein the FIR filter is a minimum phase filterwhose magnitude response is inverse of the mimicked non-linear frequencyscale, and inverting non-linear frequency scale to yield the finalequalization filter by passing the FIR filter through a set of all-passfilters by the mobile device.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a infinite impulse response (IIR) filterby the mobile device, wherein the IIR filter is a minimum phase filterwhose magnitude response is inverse of the mimicked non-linear frequencyscale, and inverting non-linear frequency scale to yield the finalequalization filter by passing the IIR filter through a set of all-passfilters by the mobile device.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a combination filter by the mobiledevice, wherein the combination filter is a minimum phase filter whosemagnitude response is inverse of the mimicked non-linear frequency scaleand the combination filter is a combination of FIR and IIR filters, andinverting non-linear frequency scale to yield the final equalizationfilter by passing the combination filter through a set of all-passfilters by the mobile device.

The method may further include synchronizing a plurality of renderingdevices in time by calculating a delay between broadcast of thecalibration signal by the mobile device, wherein the delay is the delaybetween broadcast of the calibration signal from each of the pluralityof rendering devices and receipt of the calibration signal at themicrophone, and determining a delay compensation filter by subtractingthe delay from a pre-determined maximum delay by the mobile device bythe mobile device.

The compensating for ambient noise by the mobile device may includemeasuring ambient noise characteristics by the mobile device, on themobile device detecting a period of silence in the source audio signal,measuring loudness by the mobile device, calculating frequency responseby the mobile device using FFT (Fast Fourier Transform) of the ambientnoise characteristics, calculating a digital filter by the mobile deviceusing inverse of the calculated frequency response, and estimating anoptimum volume level by the mobile device based on the ambient noisecharacteristics.

The ambient noise characteristics may comprise of loudness level ofnoise and frequency characteristics.

A-weights may be used to measure loudness by the mobile device.

In another embodiment, a computer program product comprises computerexecutable program code recorded on a computer readable non-transitorystorage medium, said computer executable program code when executed,causing a method for improving audio quality of an audio systemcomprising of a source device and at least one rendering device, themethod including improving quality of a source audio signal, if thequality of the source signal is below a quality threshold, wherein thesource audio signal is being played on the audio system, calibrating theat least one rendering device, and compensating for ambient noise.

The method may further include obtaining frequency characteristics of atleast one microphone.

The obtaining frequency characteristics of the at least one microphonemay include communicating a test signal to the source device, capturingthe test signal by the at least one microphone, on the source deviceplaying the test signal through the rendering device, determiningimpulse response of the captured test signal, inverting frequencycharacteristics of the impulse response, determining a microphoneequalizing filter using the impulse response and the inverted frequencycharacteristics of the impulse response, and using the microphoneequalizing filter to compensate for frequency characteristics of the atleast one microphone.

The determining the quality of the source audio signal may includeidentifying a detected source audio signal, fetching a small portion ofa high quality audio signal of the identified source audio signal, timealigning the fetched high quality audio signal and the detected sourceaudio signal, calculating a metric by the mobile device, wherein themetric is related to difference between the fetched high quality audiosignal and the detected source audio signal usingSq=(H*H+O*O)/(H−O)*(H−O), where H is the fetched high quality audiosignal, O is the detected source audio signal and Sq is quality of thedetected source audio signal, and comparing the metric to the qualitythreshold to determine the quality of the source audio signal.

The improving the quality of the source audio signal may includedetecting a high quality source of the source audio signal, streamingthe high quality source of the source audio signal, and transmitting thehigh quality source of the audio stream to the source device.

The calibrating the at least one rendering device may include obtainingabsolute angles of location of the at least one rendering device interms of Cartesian coordinates with respect to a reference position,determining relative distances of the rendering devices, capturing acalibration signal, wherein the calibration signal is sent to therendering device, calculating an impulse response for the calibrationsignal, wherein the impulse response is a ratio of the FFT (Fast FourierTransform) of the calibration signal to the FFT of the receivedcalibration signal, calculating a crossover filter using the impulseresponse, wherein the crossover filter is a fourth order Butterworthfilter, determining loudness of the rendering device using the impulseresponse, determining a loudness compensation by computing an average ofmagnitude of all frequency responses for the rendering devicec andcorrecting response of the rendering devices.

The determining the relative distances of the rendering devices mayinclude capturing a reference signal, wherein the reference signal isprovided and is played by the source device, and determining therelative distances of the rendering devices by calculating delays in thecaptured reference signal.

The cut-off of the crossover filter may be based on the frequencyresponse of the impulse response.

The determining loudness of the rendering device using the impulseresponse may comprises calculating energy of the impulse response.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing a finiteimpulse response (FIR) filter, wherein the FIR filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale, and inverting non-linear frequency scale to yield thefinal equalization filter by passing the FIR filter through a set ofall-pass filters.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing a infiniteimpulse response (IIR) filter, wherein the IIR filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale, and inverting non-linear frequency scale to yield thefinal equalization filter by passing the IIR filter through a set ofall-pass filters.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing acombination filter, wherein the combination filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale and the combination filter is a combination of FIR andIIR filters, and inverting non-linear frequency scale to yield the finalequalization filter by passing the combination filter through a set ofall-pass filters.

The method may further include synchronizing a plurality of renderingdevices in time by calculating a delay between broadcast of thecalibration signal, wherein the delay is the delay between broadcast ofthe calibration signal from each of the plurality of rendering devicesand receipt of the calibration signal at the microphone, and determininga delay compensation filter by subtracting the delay from apre-determined maximum delay.

The compensating for ambient noise may include measuring ambient noisecharacteristics, on the mobile device detecting a period of silence inthe source audio signal, measuring loudness, calculating frequencyresponse using FFT (Fast Fourier Transform) of the ambient noisecharacteristics, calculating a digital filter using inverse of thecalculated frequency response, and estimating an optimum volume levelbased on the ambient noise characteristics.

The ambient noise characteristics may comprise of loudness level ofnoise and frequency characteristics.

A-weights may be used to measure loudness.

In yet another embodiment, a method for obtaining frequencycharacteristics of at least one microphone associated with a mobiledevice includes communicating a test signal to a source device by themobile device, capturing the test signal by the at least one microphone,on the source device playing the test signal through a rendering device,determining impulse response of the captured test signal by the mobiledevice, inverting frequency characteristics of the impulse response bythe mobile device, determining a microphone equalizing filter by themobile device using the impulse response and the inverted frequencycharacteristics of the impulse response, and using the microphoneequalizing filter to compensate for frequency characteristics of the atleast one microphone by the mobile device.

In a further embodiment, a computer program product comprises computerexecutable program code recorded on a computer readable non-transitorystorage medium, said computer executable program code when executed,causing a method for obtaining frequency characteristics of at least onemicrophone associated with the computer program product, the methodincluding communicating a test signal to a source device, capturing thetest signal by the at least one microphone, on the source device playingthe test signal through a rendering device, determining impulse responseof the captured test signal, inverting frequency characteristics of theimpulse response, determining a microphone equalizing filter using theimpulse response and the inverted frequency characteristics of theimpulse response, and using the microphone equalizing filter tocompensate for frequency characteristics of the at least one microphone.

In yet another embodiment, a method for improving audio quality of anaudio system comprising of a source device and at least one renderingdevice using a mobile device by improving quality of a source audiosignal by the mobile device, if the quality of the source signal isbelow a quality threshold, wherein the source audio signal is beingplayed on the audio system, the method further including identifying adetected source audio signal by the mobile device, fetching a smallportion of a high quality audio signal of the identified source audiosignal by the mobile device, time aligning the fetched high qualityaudio signal and the detected source audio signal by the mobile device,calculating a metric related to difference between the fetched highquality audio signal and the detected source audio signal usingSq=(H*H+O*O)/(H−O)*(H−O), where H is the fetched high quality audiosignal, O is the detected source audio signal and Sq is quality of thedetected source audio signal, and comparing the metric to the qualitythreshold by the mobile device to determine the quality of the sourceaudio signal.

The method may further include detecting a high quality source of thesource audio signal by the mobile device, streaming the high qualitysource of the source audio signal by the mobile device, and transmittingthe high quality source of the audio stream to the source device by themobile device.

In yet a further embodiment, a computer program product comprisescomputer executable program code recorded on a computer readablenon-transitory storage medium, said computer executable program codewhen executed, causing a method for improving audio quality of an audiosystem comprising of a source device and at least one rendering deviceusing a mobile device by improving quality of a source audio signal, ifthe quality of the source signal is below a quality threshold, whereinthe source audio signal is being played on the audio system; wherein themethod further includes identifying a detected source audio signal,fetching a small portion of a high quality audio signal of theidentified source audio signal, time aligning the fetched high qualityaudio signal and the detected source audio signal, calculating a metricrelated to difference between the fetched high quality audio signal andthe detected source audio signal using Sq=(H*H+O*O)/(H−O)*(H−O), where His the fetched high quality audio signal, O is the detected source audiosignal and Sq is quality of the detected source audio signal, andcomparing the metric to the quality threshold to determine the qualityof the source audio signal.

The method may further include detecting a high quality source of thesource audio signal, streaming the high quality source of the sourceaudio signal, and transmitting the high quality source of the audiostream to the source device.

In a further embodiment, a method for improving audio quality of anaudio system comprising of a source device and at least one renderingdevice using a mobile device by calibrating the at least one renderingdevice by the mobile device includes obtaining absolute angles oflocation of the at least one rendering device in terms of Cartesiancoordinates with respect to a reference position by the mobile device,determining relative distances of the rendering devices by the mobiledevice, capturing a calibration signal by the mobile device, wherein thecalibration signal is sent to the rendering device by the mobile device,calculating an impulse response for the calibration signal by the mobiledevice, wherein the impulse response is a ratio of the FFT (Fast FourierTransform) of the calibration signal to the FFT of the receivedcalibration signal, calculating a crossover filter using the impulseresponse by the mobile device, wherein the crossover filter is a fourthorder Butterworth filter, determining loudness of the rendering deviceusing the impulse response by the mobile device, determining a loudnesscompensation by computing an average of magnitude of all frequencyresponses for the rendering device by the mobile device, and correctingresponse of the rendering devices by the mobile device.

The determining the relative distances of the rendering devices by themobile device may include capturing a reference signal by the mobiledevice, wherein the reference signal is provided by the mobile deviceand is played by the source device, and determining the relativedistances of the rendering devices by the mobile device by calculatingdelays in the captured reference signal.

The cut-off of the crossover filter may be based on the frequencyresponse of the impulse response.

The determining loudness of the rendering device using the impulseresponse may comprise of calculating energy of the impulse response.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a finite impulse response (FIR) filterby the mobile device, wherein the FIR filter is a minimum phase filterwhose magnitude response is inverse of the mimicked non-linear frequencyscale, and inverting non-linear frequency scale to yield the finalequalization filter by passing the FIR filter through a set of all-passfilters by the mobile device.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a infinite impulse response (IIR) filterby the mobile device, wherein the IIR filter is a minimum phase filterwhose magnitude response is inverse of the mimicked non-linear frequencyscale, and inverting non-linear frequency scale to yield the finalequalization filter by passing the IIR filter through a set of all-passfilters by the mobile device.

The correcting response of the rendering devices by the mobile devicemay include mimicking non-linear frequency scale of a human auditorysystem by passing the impulse response through a set of all-pass filtersby the mobile device, computing a combination filter by the mobiledevice, wherein the combination filter is a minimum phase filter whosemagnitude response is inverse of the mimicked non-linear frequency scaleand the combination filter is a combination of FIR and IIR filters, andinverting non-linear frequency scale to yield the final equalizationfilter by passing the combination filter through a set of all-passfilters by the mobile device.

The method may further include synchronizing a plurality of renderingdevices in time by calculating a delay between broadcast of thecalibration signal by the mobile device, wherein the delay is the delaybetween broadcast of the calibration signal from each of the pluralityof rendering devices and receipt of the calibration signal at themicrophone, and determining a delay compensation filter by subtractingthe delay from a pre-determined maximum delay by the mobile device bythe mobile device.

In yet a further embodiment, a computer program product comprisescomputer executable program code recorded on a computer readablenon-transitory storage medium, said computer executable program codewhen executed, causing a method for improving audio quality of an audiosystem comprising of a source device and at least one rendering deviceby calibrating the at least one rendering device; wherein the methodfurther includes obtaining absolute angles of location of the at leastone rendering device in terms of Cartesian coordinates with respect to areference position, determining relative distances of the renderingdevices, capturing a calibration signal, wherein the calibration signalis sent to the rendering device, calculating an impulse response for thecalibration signal, wherein the impulse response is a ratio of the FFT(Fast Fourier Transform) of the calibration signal to the FFT of thereceived calibration signal, calculating a crossover filter using theimpulse response, wherein the crossover filter is a fourth orderButterworth filter, determining loudness of the rendering device usingthe impulse response, determining a loudness compensation by computingan average of magnitude of all frequency responses for the renderingdevice, and correcting response of the rendering devices.

The determining the relative distances of the rendering devices mayinclude capturing a reference signal, wherein the reference signal isprovided and is played by the source device, and determining therelative distances of the rendering devices by calculating delays in thecaptured reference signal.

The cut-off of the crossover filter may be based on the frequencyresponse of the impulse response.

The determining loudness of the rendering device using the impulseresponse may comprise of calculating energy of the impulse response.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing a finiteimpulse response (FIR) filter, wherein the FIR filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale, and inverting non-linear frequency scale to yield thefinal equalization filter by passing the FIR filter through a set ofall-pass filters.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing a infiniteimpulse response (IIR) filter, wherein the IIR filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale, and inverting non-linear frequency scale to yield thefinal equalization filter by passing the IIR filter through a set ofall-pass filters.

The correcting response of the rendering devices may include mimickingnon-linear frequency scale of a human auditory system by passing theimpulse response through a set of all-pass filters, computing acombination filter, wherein the combination filter is a minimum phasefilter whose magnitude response is inverse of the mimicked non-linearfrequency scale and the combination filter is a combination of FIR andIIR filters, and inverting non-linear frequency scale to yield the finalequalization filter by passing the combination filter through a set ofall-pass filters.

The method may further include synchronizing a plurality of renderingdevices in time by calculating a delay between broadcast of thecalibration signal, wherein the delay is the delay between broadcast ofthe calibration signal from each of the plurality of rendering devicesand receipt of the calibration signal at the microphone, and determininga delay compensation filter by subtracting the delay from apre-determined maximum delay.

In a further embodiment, a method for improving audio quality of anaudio system comprising of a source device and at least one renderingdevice using a mobile device by compensating for ambient noise includesmeasuring ambient noise characteristics by the mobile device, on themobile device detecting a period of silence in the source audio signal,measuring loudness by the mobile device, calculating frequency responseby the mobile device using FFT (Fast Fourier Transform) of the ambientnoise characteristics, calculating a digital filter by the mobile deviceusing inverse of the calculated frequency response, and estimating anoptimum volume level by the mobile device based on the ambient noisecharacteristics.

The ambient noise characteristics may comprise of loudness level ofnoise and frequency characteristics.

A-weights may be used to measure loudness by the mobile device.

In a further embodiment, a computer program product comprises computerexecutable program code recorded on a computer readable non-transitorystorage medium, said computer executable program code when executed,causing a method for improving audio quality of an audio systemcomprising of a source device and at least one rendering device bycompensating for ambient noise; wherein the method further comprises ofmeasuring ambient noise characteristics, on detecting a period ofsilence in the source audio signal, measuring loudness, calculatingfrequency response using FFT (Fast Fourier Transform) of the ambientnoise characteristics, calculating a digital filter using inverse of thecalculated frequency response, and estimating an optimum volume levelbased on the ambient noise characteristics.

The ambient noise characteristics may comprise of loudness level ofnoise and frequency characteristics.

A-weights may be used to measure loudness.

What is claimed is:
 1. A method, performed by a mobile device, forobtaining a high quality version of a first audio signal that isgenerated by a first source and is being played back on an audio systemthat includes a source device and at least one rendering device, themethod comprising: identifying the first audio signal; determiningwhether a quality of the first audio signal is below a qualitythreshold; and in response to determining that the quality of the firstaudio signal is below the quality threshold, providing a location of asecond audio source that generates a second audio signal that has ahigher quality than the first audio signal or a portion of the secondaudio signal to the source device for streaming thereby.
 2. The methodof claim 1, wherein the determining whether the quality of the firstaudio signal is below the quality threshold comprises: obtaining theportion of the second audio signal from the location; time aligning theobtained portion of the second audio signal and the identified firstaudio signal; calculating a metric based on a difference between theobtained portion of the second audio signal and the identified firstaudio signal.
 3. The method of claim 2, wherein the metric is calculatedin accordance with:Sq=(H*H+O*O)/(H−O)*(H−O) where H is the obtained portion of the secondaudio signal, O is the identified first audio signal and Sq is thequality of the identified first audio signal.
 4. The method of claim 1,wherein the identifying the first audio signal comprises: detecting thefirst audio signal by at least one microphone; and identifying the firstaudio signal based on audio fingerprinting.
 5. The method of claim 1,wherein the location is remote with respect to the source device and themobile device.
 6. The method of claim 1, wherein the mobile device andthe source device are the same device.
 7. The method of claim 1, furthercomprising: streaming the portion of the second audio signal from thelocation.
 8. A computer program product comprising computer executableprogram code recorded on a computer readable non-transitory storagemedium, said computer executable program code when executed, performinga method for obtaining a high quality version of a first audio signalthat is generated by a first source and is being played back on an audiosystem that includes of a source device and at least one renderingdevice, the method comprising: identifying the first audio signal;determining whether a quality of the first audio signal is below aquality threshold; and in response to determining that the quality ofthe first audio signal is below the quality threshold, providing alocation of a second audio source that generates a second audio signalthat has a higher quality than the first audio signal or a portion ofthe second audio signal to the source device.
 9. The computer programproduct of claim 8, wherein the determining whether the quality of thefirst audio signal is below the quality threshold comprises: obtainingthe portion of the second audio signal from the location; time aligningthe obtained portion of the second audio signal and the identified firstaudio signal; calculating a metric based on a difference between theobtained portion of the second audio signal and the identified firstaudio signal.
 10. The computer program product of claim 9, wherein themetric is calculated in accordance with:Sq=(H*H+O*O)/(H−O)*(H−O) where H is the obtained portion of the secondaudio signal, O is the identified first audio signal and Sq is thequality of the identified first audio signal.
 11. The computer programproduct of claim 8, wherein the identifying the first audio signalcomprises: detecting the first audio signal by at least one microphone;and identifying the first audio signal based on audio fingerprinting.12. The computer program product of claim 8, wherein the at least onemicrophone is included in a mobile device.
 13. The computer programproduct of claim 8, wherein the location is remote with respect to thesource device and the mobile device.
 14. The computer program product ofclaim 8, wherein the method further comprises streaming the portion ofthe second audio signal from the location.
 15. A mobile deviceconfigured to obtain a high quality version of a first audio signal,comprising: at least one microphone configured to detect the first audiosignal that is generated by a first source and is being played back byat least one rendering device coupled to a source device; and aprocessing unit configured to: identify the first audio signal;determine whether a quality of the first audio signal is below a qualitythreshold; and in response to a determination that the quality of thefirst audio signal is below a quality threshold, provide a location of asecond audio source that generates a second audio signal that has ahigher quality than the first audio signal or a portion of the secondaudio signal to the source device
 16. The mobile device of claim 15,wherein the processing unit is configured to determine whether thequality of the first audio signal is below a quality threshold by:obtaining the portion of the second audio signal from the location; timealigning the obtained portion of the second audio signal and theidentified first audio signal; calculating a metric based on adifference between the obtained portion of the second audio signal andthe identified first audio signal.
 17. The mobile device of claim 16,wherein the metric is calculated in accordance with:Sq=(H*H+O*O)/(H−O)*(H−O) where H is the obtained portion of the secondaudio signal, O is the identified first audio signal and Sq is thequality of the identified first audio signal.
 18. The mobile device ofclaim 15, wherein the processing unit is configured to identify thefirst audio signal based on audio fingerprinting.
 19. The mobile deviceof claim 15, wherein the location is remote with respect to the sourcedevice and the mobile device.
 20. The mobile device of claim 15, whereinthe processing unit is further configured to stream the portion of thesecond audio signal from the location.